Plaid Cymru leader Leanne Wood said Theresa May’s vision for Brexit would not be in the Welsh national interest.
Photograph: Jeff J Mitchell/Getty Images

The leaders of the two biggest parties in Wales have said that the country should maintain some form of access to the single market after Brexit, arguing that if Theresa May rejects their ideas she must come up with a plan of her own.

Unveiling a detailed white paper on how a post-Brexit Wales might look, Labour’s Carwyn Jones, the first minister, and the Plaid Cymru leader, Leanne Wood, said May’s response was a test of how serious she was in consulting with the devolved nations.

“I don’t think the UK government will want to go to the negotiations with a public battle taking place with the devolved governments,” Jones said, at a launch event in London when asked what he would do if May rejected the ideas.

“I’m not starting from the position. I’m not interested in argument, I want us to all agree a position before those negotiations.”

The 64-page document, also devised with input from the Welsh Liberal Democrats, lays out a plan for Brexit partly comparable to Norway’s links to the EU, with tariff-free access to markets and some possible limits on free movement of people.

Keeping open a series of options on both themes, the white paper calls for tariff-free access to the EU’s single market, possibly through membership of the European Free Trade Association. Freedom of movement would be “linked to employment”, other than for students or those able to support themselves.

Jones said the plan could be used as “an alternative path” for Brexit for the entire UK.

He stressed that none of the parties were seeking to overturn the June vote on membership: “It’s time to move on beyond the referendum. No one’s trying to re-fight it.

“What we don’t accept is that the people of Wales voted for less inward investment, for a weaker economy and for fewer jobs.

“Severing ties with the single market to control our borders would be an act of catastrophic self-harm. Last June the people of Britain didn’t vote to be done over, but they did vote for change.”

May’s speech last week giving her first details on a Brexit plan would appear to have ruled out the single market option in the Welsh white paper.

Wood said, however, that May’s vision was not acceptable: “It was an option which was not on the ballot paper and would not, in our view, be in the Welsh national interest.”

Both she and Jones stressed that if May was unable to accept their ideas, it was up to her and her ministers to explain in detail how else they would manage the process.

“There will be people who don’t accept what’s in that document, who don’t agree with it,” Jones said.

“Fine – it’s a democracy. But the challenge, as we’ve outlined, is to produce your own plans in detail. Put your back into it, don’t just say, ‘It’ll all be easy, it’ll all be fine’, which is what we’ve had so far.”

Wood agreed: “If she wants to reject this, then what is her alternative plan for Wales? We’ve not seen her produce a plan for the UK yet, in any detail.

“We take the prime minister’s words at face value – we are entering into the process in that spirit.” However, Wood said, her party “already has a plan B” for Brexit, in case the prime minister did not support them.

The white paper has already been dismissed by the leader of the Welsh Conservatives, Andrew RT Davies.

“After seven months of flip-flopping, dithering and denial, the leftwing political establishment in Wales has clubbed together a late, half-baked plan in the effort to remain relevant and credible – ignoring many of the reasons why people voted to leave the European Union,” he said.

“Sadly, this ‘plan’ for Brexit has only sought to appease their own in the Cardiff Bay bubble – lacking serious consensus across the political spectrum and showing a blatant disregard for the wishes of the Welsh public.”